Tel me about it, one of our engineers removed a neutral link as well as disconnect the 3 phases with the isolator but forgot to put the link in before switching on, PLC & 4 inverters + PSU lit up like a Christmas tree as these were all single phase devices split between phases. Tip never install removable neutral links and if required, use 4 pole isolators if neutral needs to be disconnected. The neutral should be at the same potential as the earth (usually tied at source), however this cannot be guaranteed due to resistance of cables so disconnecting neutral with the phases is not a bad idea.